Materials handling device



Jan. 9, 1968 v. J. KOVARIK- MATERIALS HANDLING DEVICE 2 Sheets-Sheet 2 Filed on. 11, 1965 2 m f V fix 0 K J T V v/ 3 QUE United States Patent f 3,362,547 MATERIALS HANDLING DEVICE Vincent J. Kovarik, Rte. 2, Imperial, Mo. 63052 Filed Oct. 11, 1965, Ser. No. 494,521 5 Claims. (Cl. 214-77) ABSTRACT OF THE DISCLOSURE A platform translatable vertically and horizontally with respect to a base; levers pivotally connected to the platform at points spaced horizontally and laterally but in substantially a common horizontal plane, and pivotally connected to horizontally and laterally spaced supporting brackets beneath the base. The levers are connected by a link connected to the levers intermediate but offset from a line between the pivotal connections of the respective levers to the platform and to the supporting bracket to which each lever is pivoted. The link and levers constitute a parallel linkage by which the platform can be moved between a position at which the platform extends within a bay in the base and a position at which the platform is below and entirely beyond the edge of the base. In the course of this movement, the levers move 180. One of the levers is a bell crank, the other a platform lever with an offset foot, the end of which is connected to the platform. The link, pivoted to the bell crank lever at one end and to the platform lever at the other end, constitutes a drive connection between the levers and piston rod from a hydraulic cylinder is connected to the platform lever.

Background 0 the invention This invention relates to heavy materials handling equipment, and has particular but not exclusive application to such equipment in combination with a vehicle.

While there are many so-called lift gates such as the one shown in Patent No. 2,654,491, all materials lifting systems adaptable to vehicles, now in use, have several inherent limitations which, until the present time, have proved almost insuperable. Among these faults has been the need for hand labor to place the materials to be lowered and raised on and off the lift. This fault is compounded by the discontinuity between the lift fioor plane and the planes of the surfaces from which and to which the materials are to be moved. In the case of vehicles, there has generally been heretofore a bump or gap between the vehicle body floor and the lift surface, when the lift is in its upper position, and a considerable distance between the ground and the lift floor when the lift is in its lower position. A further fault of systems known heretofore has been the fact that the lift gate is liable to interfere with dock loading and unloading, because to avoid having the lift surface project rearwardly when not in use, it is now common to fold the lift platform upwardly across the rear of the vehicle, or downwardly, which puts it between the vehicle and the dock.

Still another fault of the present lift gate mechanisms is the limited weight which most of them are capable of handling.

One object of this invention is to provide a materials handling device which allows substantially greater weights to be handled for the same sized elements of the device, than device known heretofore.

Another object of this invention is to provide a materials handling device which presents no obstacles to convention-a1 dock loading and unloading procedures.

Another object of this invention is to provide a materials handling device which will allow pallets to be used in cases where no dock is available.

3,362,547 Patented Jan. 9, 1968 "ice Another object of this invention is to provide a materials handling device which is relatively inexpensive to manufacture and which is relatively foolproof in operation.

Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawings.

Summary of the invention In accordance with this invention, generally stated, a materials handling device is provided in which a platform is moved from a position substantially flush with a materials carrying surface such as the bed of a truck, to a lower position, translated a substantial distance, while remaining level. To this end, in the illustrative embodiment shown, in which the device is mounted on and combined with a vehicle, at least two substantially identical sets of link members are suspended beneath the body of the vehicle and are connected to a platform at pivot points spaced horizontally of the platform in such a way that the link members carry the platform from a position at which it forms a part of the bed to a position at which it is closely adjacent the ground. The height of the platform from the ground can be adjusted. The platform may be a broad, uninterrupted plate or it may consist of two or more arms to facilitate lift truck handling of pallets from the lowered position.

Means are provided for moving materials from the rear of the truck bed to the platform without manual trucking.

The form and substance of the invention will become evident in the following specification and appended drawings in which:

Brief description of the drawing FIGURE 1 is a horizontal longitudinal sectional view of a truck body, revealing a plan view of an illustrative embodiment of a materials handling device of this invention mounted on a truck bed with the extreme lateral position of the lift arms (platform) of the materials handling device shown in dotted lines;

FIGURE 2 is a fragmentary sectional view taken along the line 22 of FIGURE 1;

FIGURE 3 is a view partly in section and partly in end elevation taken along the line 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary vertical longitudinal sectional view of the device shown in FIGURE 1, revealing a view in side elevation of the parts of the linkage mechanism, which are normally hidden from view, in the upper position of the platform and in dotted line, in one of the positions of the platform intermediate its upper and lower position as well as several intermediate positions of the lift arms themselves; and

FIGURE 5 is a sectional view corresponding to that of FIGURE 4, revealing a view in side elevation of the linkage system and platform in the lowered position.

Description 0 the preferred embodiment Turning now to the drawings for one illustrative embodiment of materials handling device of this invention, reference numeral 1 indicates a truck body with a bed 7 The bed 7 is provided with a winch chain slot 4, running longitudinally of the bed and defined by angle irons 44 spaced facing horizontal legs of which form a pallet skid sup-port. The bed also has in its upper surface a pair of longitudinally extending skid guiding channels 5 parallel with the winch chain slot. Mounted on a cross member 18 under the bed is a winch drive 2, which, in the embodiment shown, includes a conventional hydraulic motor and drive sprocket. A winch chain 3 extends around the drive sprocket, with its upper reach along and immediately beneath the chain slot 4, and around an idler 14 mounted on a cross member 19 beneath the bed '7. The idler 1 is positioned so that the chain 3 passes close to the back edge of the truck body but does not project behind it. The cross members 13 and 19 are cut away at their upper edges in the area of the chain slot, to accommodate the upper reach of the chain 3.

The bed '7 is also cut away from it rear edge to provide two lift-arm bays 6.

A pair of heavy I-beams 9, part of the truck frame, extend longitudinally of and beneath the bed 7 outboard of the bays 6. Attached, as by welding, to the inboard sides of the l-beams 9 at the rear of the truck bed are heavy sup-porting brackets 10. The supporting brackets 10 are offset inwardly toward one another below the beams 9, as shown in FIGURE 3.

A forward control link bracket an and an intermediate link bracket 27, positioned between the forward control link bracket 26 and the supporting bracket Til, are also secured, as by welding, to each of the l-beams 9, as shown in FIGURES 4 and 5.

A platform in the embodiment shown consists of two arms or forks 15. Each of the arms is of a length and width to fit loosely in the bays 6. The arms 15' have a flat top and, beneath the top, longitudinal ribs 55 which serve as strengthening members and also to provide a pivot-supporting wall.

A bell crank lever 12 is pivoted at as at one end to-a rib 55 approximately three-fifths of the distance toward the rear edge of the fork l5, and, at 37, at its other end, to the bracket The bell crank lever 12 is crooked to form two arms 112 and 212.

A triangular platform lever 11 has right angled legs 311 and 43-11, a hypotenuse 511 and an angled foot ilil projecting as a continuation of the hypotenuse 511 and extending parallel to the leg an. The end of the angled foot 111 is pivoted at 35 to a rib 55 outboard of the bell crank lever '52, and, at 32, at an apex 211 of the leg 311 and the hypotenuse 511 to the intermediate bracket 2'7. A platform link 16 i pivotally connected at one end, at 33, at the apex of legs 311 and r ll to the platform lever 11. The other end of the platform link 16 is pivoted, at 24, to the arm 112 of the bell crank lever 12.

A drive link is pivotally connected, at 38, at one end to the hypotenuse 511 of the triangular platform lever 11, and, at its other end, is pivotally connected at 39, both to a clevis 24 on the end of a piston rod 22 and to one end of a control link Ell. The other end of the control link 20 is pivoted at 31 to the forward control line bracket 26.

The piston rod 22 is connected to a piston, not here shown, in a hydraulic cylinder 21, the end of which op posite the piston rod is pivotally mounted, at 23, on a plate on the I-beam 9, so as to be clear of the lower flange of the l-beam. Hydraulic connections to the cylinder from a hydraulic pump, not here shown, are provided with the usual controls selectively to move the piston, hence the piston rod 22, forwardly and rearwardly.

The pivots 31, 32 and 3'7 on the brackets 26, 27 and 10 respectively lie in a common plane parallel to the plane of the bed 7. The link 16 is pivoted to the lever lit at 33 at the same distance from the pivot 32 as it is pivoted to the bell crank lever 12 (at 34') from the pivot 37, and the leg 3A of the platform lever 11 and the leg 112 of the bell crank lever are parallel. The two pivot points 35 and 36 lie in a common plane parallel with the upper surface of the arms 15.

This arrangement of pivot points and levers ensures a parallel linkage which keeps the arms 15 parallel with the truck bed. Parallel linkages are not by any means broadly new, but, and this distinguishes the present materials handling device from those known heretofore, the pivot points 35' and 3-6 are spaced well apart in a direction lengthwise of the platform (arms 15) as distinguished from being spaced vertically in a line, and at the same time, the arrangement of links, levers and driving system of this device are such as to enable the platform to be moved between a position at which it forms a part of the bed structure itself, entirely within the perimetric boundaries of the bed, and a position both vertically offset from and entirely removed to the rear of the bed. The path of the platform 15 is illustrated in FIGURES 4 and 5.

Assumin that the platform is in the position at which it is seated in the bays 6, and that a pallet has been positioned over the arms 15, hydraulic fluid admitted to the forward end of the cylinder 2 drives the piston rod 22 forward, rocking the control link 20 about its pivot 31 while moving the link 25 rearwardly. T e movement of the link 25 moves platform lever 11 about its pivot 32 which in turn, through the agency of platform link 16, moves the bell crank lever 12 about its pivot 37.

The immediate effect upon the platform is to move it upwardly and rearwardly. The upward movement of the platform ensures that the pallet on the bed will be raised from the bed and carried, free of the bed, by the platform. As the piston rod 22 continues to travel rearwardly, the platform clears the rear of the bed, and, toward the end of the stroke, reaches the ground. if the platform is made with substantial thickness, so as to give clearance between the underside of the platform and the upper edge of the arm and foot H3, or if appropriate slots are provided in the top surface of the platform, the platform can be lowered a short distance farther than the position at which the arm 212 and foot Til are parallel with the ground. This provides tolerance to accommodate differences in height of the bed in response to different loading conditions, tire pressure and the like. It is also apparent that the length of the brackets 1t and 27 can be made adjustable. If they are so adjusted as to bring the platform level below that of the upper surface of the bed, no great harm is done, since the platform rises a substantial distance initially.

in loading a truck from the ground, or on merely returning the platform to its position in the truck, hydraulic fiuid is admitted to the rearward end of the cylinder 21 and released from the forward end, and the platform returns in exactly the opposite sequence from the one described above.

It can be seen that the arms 15 can be bridged over with a plate to form an uninterrupted platform, and the truck bed can either be cut away or recessed to accommodate it, or the plate can rest on the bed intermediate the arms. The unbridged arms are particularly adapted to accommodate palletized loads. Suitable hooks or dogs on the winch chain 3 engage the forward edge of a pallet the skids of which ride in the channels 5 and the skid support formed by the angle irons 44, as shown in FIG- URE 2. When the winch is driven in the direction in which the upper reach of the chain moves rearwardly, the pallet is moved rearwardly until it is positioned over the platform 15.

It can be seen that, with a suitable fence or other means of attachment or positioning, other types of freight can be moved by means of the winch, onto the platform.

Numerous variations in the construction of the device of this invention, within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure. Thus, for example, different kinds of driving means may be employed, although the hydraulic cylinder has numerous advantages. The links and levers may be differently shaped and difi'erently constructed, as long as they are arranged to clear one another when they move through substantially as shown in FTGURES 4 and 5. These are merely illustrative.

It can be seen that the device is entirely out of the way if the truck is to be loaded at a dock; that, because of the relatively widely spaced pivot. points 35 and 35, the device is extremely strong and rigid for its weight, and that it provides a simple, highly effective means for loading and unloading between the ground and the bed of a truck. It can also been seen that the mechanism can be employed in other applications, but that it is particularly adapted for use in a truck.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In combintion with a material-carrying base from which materials are to be removed and to which they are to be conveyed, said base having a platform-receiving bay extending through said base from an edge thereof, a materials handling device by which materials can be translated vertically and horizontally with respect to said base, comprising platform means extending at one position within said bay, lever means pivotally connected to said platform means at points spaced horizontally and laterally from one another, and pivotally connected to horizontally and laterally spaced supported brackets beneath said base, a connecting link between said lever means, said connecting link having two ends and being pivoted at one end to one of the lever means intermediate the pivotal connections of said lever means to its supporting bracket and the platform and offset from a straight line between said pivotal connections, and pivoted at its other end to another of said lever means intermediate the pivotal connections of said other lever means to its supporting bracket and the platform and offset from a straight line between said pivotal connections, said link and levers constituting a parallel linkage, and power means for moving said levers through substantially 180 between a position at which the platform extends within said bay and a position at which the platform is below and entirely beyond the said edge of the base.

2. The combination of claim 1 wherein the lever means are a bell crank lever, and a platform lever having an offset foot the end of which is connected to the platform, said link, pivoted to the bell crank lever at one end and to the platform lever at the other end, constitutes a driving connection between the levers, and said power means is connected to the platform lever.

3. The combination of claim 2 wherein a drive link is pivotally connected at one of its ends to the platform lever and at the other of its ends to a reciprocating drive means, and a control link, pivoted at One end on a fixed bracket below the base is pivotally connected at its other end to the drive link.

4. The combination of claim 3 wherein the drive means includes a hydraulic cylinder.

5. The combination of claim 3 wherein the platform lever has a triangular part, the lever-connecting link is pivoted at the right apex of said triangular part, and the drive link is pivoted to the hypotenuse.

References Cited UNITED STATES PATENTS 2,521,727 9/1950 Kappen 214-518 2,536,954 1/1951 Olsen 214-77 X 2,576,881 11/1951 Kern 214-77 2,779,488 1/1957 Trotter et al. 21477 3,184,082 5/1965 Hall 21477 FOREIGN PATENTS 498,529 12/1953 Canada.

ROBERT G. SHERIDAN, Primary Examiner. 

